The level of cover you receive can vary a great deal from insurer to insurer but the average annual travel insurance policy should at least include:
Cancellation and delay cover
Loss of baggage cover
Other types of cover included in a comprehensive annual multi trip policy could include: cover for valuables and holiday money, scheduled airline failure insurance, personal accident/personal liability cover and legal expenses cover.
As a good rule of thumb, you should aim to have the following amounts in each area of cover:
Medical cover in the region of £2 million (double this if travelling to the USA). This should also cover the cost of emergency repatriation.
Personal liability cover amounting to around £1 million.
Cancellation cover of equal value to your holiday (including the cost of prepaid excursions). Cover is usually on a per person basis so to cover a £2,000 holiday you'd need cover of £1,000 each as a minimum.
Baggage and personal possessions cover to cover the cost of replacing your suitcase and contents should it be lost or stolen. You should also consider the cost of single items such as your digital camera or laptop and factor this into the cover level you require (it is commonplace for insurers to apply a cap to the amount you can claim for on any one item so read the terms and conditions of your policy carefully).
Holiday spending money cover of around £500 or equal to the value of the cash you will be taking with you.